Secondary structure transitions and aggregation induced in dynorphin neuropeptides by the detergent sodium dodecyl sulfate

Loïc Hugonin, Andreas Barth, Astrid Gräslund*, Alex Perálvarez-Marín

*Corresponding author for this work

Research output: Contribution to journalArticleResearchpeer-review

21 Citations (Scopus)


Dynorphins, endogeneous opioid neuropeptides, function as ligands to the opioid kappa receptors and also induce non-opioid effects in neurons, probably related to direct membrane interactions. We have characterized the structure transitions of dynorphins (big dynorphin, dynorphin A and dynorphin B) induced by the detergent sodium dodecyl sulfate (SDS). In SDS titrations monitored by circular dichroism, we observed secondary structure conversions of the peptides from random coil to α-helix with a highly aggregated intermediate. As determined by Fourier transform infrared spectroscopy, this intermediate exhibited β-sheet structure for dynorphin B and big dynorphin. In contrast, aggregated dynorphin A was α-helical without considerable β-sheet content. Hydrophobicity analysis indicates that the YGGFLRR motif present in all dynorphins is prone to be inserted in the membrane. Comparing big dynorphin with dynorphin A and dynorphin B, we suggest that the potent neurotoxicity of big dynorphin could be related to the combination of amino acid sequences and secondary structure propensities of dynorphin A and dynorphin B, which may generate a synergistic effect for big dynorphin membrane perturbing properties. The induced aggregated α-helix of dynorphin A is also correlated with membrane perturbations, whereas the β-sheet of dynorphin B does not correlate with membrane perturbations.

Original languageEnglish
Pages (from-to)2580-2587
Number of pages8
JournalBiochimica et Biophysica Acta - Biomembranes
Issue number11
Publication statusPublished - Nov 2008


  • Aggregated intermediate
  • Circular dichroism
  • Dynorphin
  • Fourier transform infrared spectroscopy
  • Secondary structure transition
  • Sodium dodecyl sulfate


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